A seemingly simple but powerful feature of Lightroom is the History panel. The History panel lists all the changes you have made to an image inside of Lightroom. With Lightroom 5, this also includes edits that you made to smart previews on a different computer.
In the Develop module, the History panel will be on the left and, if it’s collapsed, might go unnoticed. Expand the panel to behold its glory.
In the image to the left, you can see the history for my image, from import to export and beyond. For edits, each line consists of the adjustment that was made, the change in value (positive or negative), and the resulting value. So for example, for the change underneath the highlighted Export line, the adjustment was a vibrance change of -4 from 21 to 17 (the bold text representing the numbers in the window).
You can hover your mouse over one of the edits to see the thumbnail of what the image looked like at a point in the history, and click on an edit to update the main image to reflect the image at that point. Unconstrained by the laws of physics, you can move forward and backward, bending the boundaries of space and time to your will.
Einstein would not approve.
In addition to making time travel an everyday occurrence, the History panel provides some other useful features that are much less likely to produce a black hole.
If you ^ + Click (or right-click for our Windows friends) on any of the items in the History list, you have a few options.
The first option is to create a snapshot at the point of the edit. So if you start to venture down a path but aren’t too sure where it’s headed, you can create a snapshot a few steps back to retrace your steps without first having to undo changes you have already made. Mile markers. In time!
The second option you have allows you to use the Before/After feature of Lightroom to compare your current image with any point in your history. It’s kind of like the movie Looper, except you don’t need to kill the older you so that the before you can kill the older you later on. Or something. I’m confused.
Become a time traveler. Use the History panel in Lightroom to retrace your steps and learn from the past. History is cool.
So is physics.